How To Clean Windows Like A Pro
By: Joe D'Agnese, This Old House magazine
Ideally, windows should be washed twice a year, but it's a task most people don't look forward to. Part of what makes window washing such a chore is that homeowners insist on doing it with wadded-up paper towels or newspaper, spray cleaner, and a ton of elbow grease.
"All that rubbing isn't a good idea," says Brent Weingard, owner of Expert Window Cleaners in New York City. "You're just moving dirt around from one spot to another and putting a static charge on the glass, which attracts dust and dirt. As soon as you finish, the window looks dirty again."
As Weingard demonstrates on the next few pages, it's easier and more effective to clean glass like the pros do: with a squeegee and a few other readily available tools. The techniques aren't complicated, he says, and the results may surprise you.
"I don't know of anything that can transform living spaces so well. You don't know what you're missing until you do the windows."
Cleaning a Picture Window
Picture windows call for large tools. The long cloth head of a strip applicator soaks up a lot of soapy water and knocks dirt loose without scratching the glass. For a cleaning solution, Weingard uses just a squirt of dishwashing liquid in a bucket of warm water — the less suds, the better.
Starting at the top left, pull the squeegee over the soapy pane in a reverse-S pattern (left- handers would start at the top right). At the end of each stroke, wipe the squeegee's blade clean with a lint-free rag. Cloth diapers or old linen napkins are perfect for this task.
Remove any water remaining on the edges of the glass with a damp, wrung-dry chamois, which soaks up wetness without leaving streaks. Dry the windowsill with a rag.
Cleaning a Multipane Window
Customize the Squeegee
To clean a divided-light window, you need a squeegee that fits the panes. Weingard uses a hacksaw to cut one to size. He trims the metal channel ¼ inch narrower than the window pane, then files the cut edges smooth. With a utility knife, he cuts the rubber blade to the pane's full width and fits it into the channel so that it projects 1/8 inch at each end.
Scrub the panes
A handheld sponge or hog-bristle brush works best on multipane windows. Weingard prefers natural sponges. "They're firmer and more absorbent than synthetics," he says. Using the same solution of a squirt of liquid soap in water, he rubs each pane from left to right, top to bottom, working the sponge edges or brush bristles into the corners to loosen dirt.
Pull the squeegee down each pane in a single stroke from top to bottom. After each stroke, clean the blade with a rag so it doesn't leave streaks. (If the squeegee squeaks a lot, add a bit more soap to the water.) As above, remove any streaks on the glass with a chamois, and dry the muntins and sill with a rag.
Out, Out, Darned Spots
Over time, hard-water runoff from masonry or rain falling through metal window screens leaves stubborn mineral stains on glass that normal washing can't erase. So after a regular cleaning, Weingard wets the glass and gently "supercleans" it either with fine 000 steel wool (if the panes are small) or with the cleansing powders Zud or Barkeeper's Friend, which contain oxalic acid. (Other brands of powder may scratch the glass or fail to remove stains.) He mixes the powder into a paste on a wet towel, rubs away the stains, then rinses and squeegees the glass twice to remove the residue. Even with that treatment, the staining generally comes back in about six months.
To get rid of stains for good, Weingard recommends the application of 3 Star Barrier Glass Surface Protectant, a clear polymer coating. "After the stains are gone, you just put the coating on with a strip applicator and squeegee it off," he says. Protection against staining is permanent, as long as the polymer is reapplied after each regular cleaning.
Windows That Wash Themselves
Given people's aversion to washing windows, it's no wonder that at least two companies, Pilkington and PPG Industries, now make glass that cleans itself. The secret ingredient is titanium dioxide, a metallic compound that's permanently embedded in the surface of the molten glass during manufacture but doesn't affect its transparency. When exposed to the sun's ultraviolet rays, the titanium dioxide kicks off a chemical reaction that disintegrates organic dirt, such as tree sap, pollen, and dead bugs. The coating also makes the glass hydrophilic; that is, water doesn't bead up but spreads out in sheets that slice off loosened debris like an invisible squeegee. "It doesn't leave glass sparkling like it came out of the dishwasher," says Chris Barry, director of technical services for Pilkington, "but it's still quite clean." Windows with self-cleaning glass cost about 20 percent more than ordinary windows but need cleaning only about half as often.